Uniqlo's well-made, well-priced casual clothing has become a global retail phenomenon. Can its iconoclastic CEO bring some of that magic to Japan?

Uniqlo's flagship in Tokyo. The company aims to have 200 outlets in the U.S.

The strangeness of Tadashi Yanai is best appreciated in his natural element. Among the gray suits of corporate Japan, the head of Uniqlo stands out like beefsteak on a plate of sushi. In a business culture where senior executives tend to speak in soft monotones, stick to carefully vetted talking points and shuffle uncomfortably at personal questions, Yanai, 64, is as colorful as the T-shirts and sweaters in his stores. Talking so loudly that he drowns out his translator, Yanai is bracingly blunt on subjects ranging from the state of the Japanese economy ("We are on the edge of a cliff")...